Printing telegraphy



A 1,627 445 May 3 1927' F. MccoRMlcK PRINTING TELEGRAPHY Filed JUlYlG, 1926 5 Sheets-Sheet l iBY guaio, @M M 7W@ ATTORNEY 5 May 3 1927.

F. MCCORMI'CK PRINTING y'Premsa'www! Filed aulne. 192e 5 sheets-sheet 2 www 3 1 May 927 F. MccoRMlcK PRINTING TELEGRAPHY Filed July 16. 1926 5 Sheets-Sheet 3 INVENToR fw/er/VC (afm/dr ATTORN EY May 3, 1927.

F. MCCORMICK PRINTING TELEGRAPHY Filed Julyl. 1926 5 Sheets-Sheet 4 Mii,

ATTORN EY 3 1 May 927 F.MccoRM|cK PRINTING TBLEGRAPHY Filed July 16, 192e 5 sheets-sheet 5 ATTORNEYS Patented May 3, 1927.

UNITED STATES 1,627,445 PATENT OFFICE,

FOWLER MQCORMICK, OF CHICAGO, ILLINIS.

PRINTING 'rELEGRArmL Application led July 16, 1926. Serial No. 122,806.

The present invention relates to telegraphy ind more especially printing telegraphy, and it has for one of its objects the provision of a printing telegraph system in which received messages can be printed in a plurality of colors and, in addition, in a plurality of kinds of type, as for example, capital letters and lower case letters.

In my co-pending application Serial No. 74,454, tiled December 10, 1925, there is described a printing telegraph system wherein received messages can be printed in two colors-the principal object in that case being to print alternate sentences in one color and the remainingr sentences in a diierent color thereby clearly setting o'l' consecutive sentences without resorting to' the use of the word stop or other equivalent sentence terminating words as is commonly done 1n writing te-legrams. The system described herein is capable of operation in the same manner as that of my aforementioned copending application, but, in addition, the present invention provides an arrangement in which alternate sentences can be printed in one kind of type and the remaining sentences in different kinds of type-instead of different colors.

Quite independently of the feature above referred to whereby consecutive sentences can be set off, the present invention/is characterized by a provision for printing received` messages with bothy capitals and lower case letters and in a plurality of colorsall 11ndcr the control of the transmitting operator. The latter may shift from capitals to lower case letters and vice versa and from one color to another at will, exactly as in the operation of an ordinary two-color typewriter.

A printing telegraph system in accordance with this invention and which is especially adapted for transoceanic cable transmission is illustrated by way of example, in the accompanying drawings, wherein:

Fig. 1 represents the transmitting end of a printing telegraph system;

Fig. 1a is a side elevation of a transmitter.

Fig. 2 illustrates the receiving end of the system;

Fig. 3 is a diagram of the local circuits of the receiving apparatus;

Fig. 4 is a view taken along the line 4--4 of Fig. 2 illustrating the type wheel mechanism;

Fig. 5 is a view taken along the line 5d5 of Fig. 2 illustrating-the color changing mechanism;

Fig. 6 is a view taken along the line 6-6 of Fig. 2 illustrating the electromagnetic escapement mechanism for controlling the rotation of the type wheel;

Fig. 7 is a View along the line 7 7 of Fig. 2 illustrating, particularly, the tape ang ribbon feed and printing mechanism; an

Fig. 8 is a View taken along the line 8-8 of Fig. 2 illustrating the printing magnet and its armature and the ribbon feed ratchet.

In the system illustrated in the accompanying drawings and described herein an arrangement is provided at the transmitting station whereby, normally, a continuous series of alternate positive and negative electrical impulses are impressed across a pair of cable conductors. These impulses are amplified at the reoeivipg end of the cable by means of a suitable multistage vacuum tube amplifier. The amplified impulses at the receiving end are impressed on an electromagnetic step-by-step cscapement mechanism which controls the operation of a frictionally driven shaft on which is mounted a type wheel. At all times, when no signal.

is being transmitted, the type wheel rotates continuously, step-by-step, under the control of the -escapement mechanism which operates continuously during the absence of signal or printing impulses.

In response to the actuation, at the transmitting station, of a key corresponding with a letter, numeral or punctuation mark which it is desired to transmit and print at the receiving station or a key which controls the color changing or type shifting mechanisms at the receiving station, the polarity changing device at the transmitting station is momentarily stopped. Thereupon an electrical impulse of relatively long duration, compared with the duration of the normal impulses, is transmitted. At the receiving station 4there is a printing electromagnet which is under the control of a pair of slow acting relays-the operation of either of which will close a circuit for the printing magnet. The printing magnet control relays just referred to are connected in circuit with the output of the receiving amplitier but are designed to be so slow acting' that they do not operate in response to the short impulses normally transmitted. When,

howeveigimpulses of longer duration caused by operation of the transmitting keys are received one or the other of the printing magnet control relays is energized for a long enough time to permit it to pull up its armature thereby closing the local circuit of the printing magnet. At the same time the operation of the normally continuously acting electromagnetic step-by-step escapement mechanism controlling the operation of the type wheel is interrupted and the type wheel is thereby brought to a standstill.

Energization 'of the printing magnet causes the immediate actuation of a printing roller between which and the type wheel a paper tape and a two-color typewriter ribbon are disposed. Any character on the type wheel which happens to be in the printing` position when the printing magnet is energized is impressed on the paper tape. But the t pe wheel rotates in synchronism with a rotating drum aty the transmitting station which starts and stops under the control of the transmitting keys. Therefore, the character on the type wheel which is in the printing position at any time when the latter is stopped in response to the operation of a key at the transmitting station, is the character corresponding to the key which is operated.

Means are provided for moving the paper tape and the two-color ribbon longitudinally step-by-step-the paper tape being moved one step after each printing or spacing actuation of the printing magnet thereby being positioned to receive the next impression.

There are two shifting electromagnets forming parts ofthe apparatus. One of these functions to shift the two-color ribbon and the other functions to shift the type wheel axially from one of its two operating positions to the other and back. The type wheel is provided with two parallel peripheral rows of charactersone row including capital letters and the other lower case letters. Therefore, when the type wheel is in one of its two operating posltions capital letters are printed and when it is in the other position lower case letters are printed. Shifting of the type wheel back and forth from one operating position to the other and shifting of the two-color ribbon may be done automatically at the end of each sentence or these shifting operations may be accomplished entirely under the control of the transmitting operator and at his will.

The apparatus and circuits are so arranged that messages may be printed with consecutive sentences in different colors such, for example. as red and black-the color being changed automatically each time a period, question mark or exclamation mark is transmitted. The apparatus and circuits are also designed for printing messages with consecutive sentences in different kinds of type-capitals and lower case letters alternately. It should be understood that when consecutive sentences are printed in different colors they are not also printed in different kinds of type; and when consecutive sentences are printed in different kinds of type they are not also printed in different colors. In other words, changing type and changing colors for consecutive sentences are alternative ways of accomplishing the same object-that object being to set oil' the sentences in a distinctive manner so as to avoid the necessity for using the word stop or equivalent expression as a sentence terminator.

When messages are to be printed using capitals and lower case letters alternately for .setting olf consecutive sentences the type wheel is automatically shifted from one of its twok operating positions to thev other whenever a period, question mark, or exclamation mark is transmitted, indicating the end of a sentence. Likewise when messages are to be printed with consecutive rentences in different colors the two-color ribbon is shifted automatically whenever a period, question mark or exclamation mark is transmitted indicating the end of a sentence.

Alternatively, the system can be operated without automaticallyy shifting from one color to another or from one style of type to another at the end of each sentence and when so operated the operator at the transmitting end of the system can control the type wheel shifting mechanism and the ribbon shifting mechanism at the receiving station and is thereby enabled to utilize both capital and lower case letters as well as two colors in transmitting messages. It is, therefore, possible with this system to automatically print a received telegraph message with the same variety and flexibility as to type and color as can be done with an ordinary two-color typewriter.

In Fig. l, l represents a portion of the frame of a transmitting typewriter an end view of which is shown in Fig. 1a. Journaled in the frame of the transmitting typewriter is a shaft 2 which, normally, is rotated continuously by au electric motor il to which it is connected through the medium of a pair of engaged friction wheels 4 and 5.

A cylindrical drum 6 is mounted on and rotates with shaft 2. Around the periphery ot' the drum 6 and arranged in a helical line are a considerable number of radially projecting pins 7. Each one of the pins 7 corresponds with a letter. numeral or other character or a space on the type wheel al the receiving station except two pins which have to do respectively with the operation of the color shifting 'and type wheel shifti 6 and shaft 2 will rotate until the pinis engaged bythe lug whereupon the drum and shaft are brought to a sudden stop. The friction drive permits of this being done without stalling the driving motor 3. Obviously, the drum 6 stops in a denite predetermined position in response to the depression of each key 8.

A crown wheel commlutator 10 comprising two interengaged half-portions 10a and 10b insulated from each other and from the shaft 2 is mounted on the latter and rotatable therewith. It will be seen that the al-` ternate segments of the commutator thus formed are integral with one of the two half-portions 10'* or 10b and that the remaining segments are integral with the other half-portion of the commutator.

A brush 11 is in wiping engagement with the hub of the commutator part 10 and another brush 12 is in wiping engagement with the hub of the other commutator part 10". Athird brush 13 is in wiping engagement with the commutator segments. As

the commutator rotates the brush 13 makes contact with the segments of half-portions 10 and 10b alternately.

Two batteries 14 and 15 are connected respectively to the brushes 11 and 12.' The negative terminal of the battery 14 is connected to the brush 11 while the positive terminal of battery 15 is connected to brush 12. The other terminals of the batteries 14 and 15 are connected in common to the cable conductor 16, and the brush 13 is connected to the cable conductor 17. Normally, that is when no transmitting key 8 is depressed, the commutator 10 rotates continuously in unison with drum 6 with the result that the voltages of batteries 14 and 15 are alternately im ressed across the conductors 16 and 17. he numberof conducting segments on the commutator 1() corresponds with the number of pins 7 and likewise with the number of keys 8 as well as the number of angular operating positions of the type wheel at thc receiving station. There is a commutator segment on crown wheel 10 corresponding to each pin 7 and to each stopping position of the type wheel at the receiving station. Theshaft 2 rotates at a fairly rapid rate so that the duration of each normal impulse transmitted is quite short.

In transmitting a message the keys 8 are operated, one at a time, and a copy of the message being transmitted is transcribed or may be transcribed by the transmitting operator at the transmitting station.`

When a transmitting key 8 is depressed and the commutator 10 thereby brought to a momentary stop the brush 13 is in contact with one of the commutator segments, and a current impulse from one or the other of the batteries 14, 15 of relatively long duration, is impressed upon the cable conductors. The duration of the impulse is, of course, equal to the duration of time the brush 13 is in contact with the commutator segment.

At the receiving end of the cable (see Fig. 2) there is a vacuum tube amplifier preferably of the resistance coupled type. This will usually be found necessary on long lines in order to bring the received impulses up to suflicient strength to operate the printing apparatus at the receiving end of the line.

A three stage push-pull resistance coupled vacuum tube amplifier of a-t pe suitable for the purpose is illustrated in ig. 2. The first two stages of this amplifier each comprise two three-electrode vacuum tubes 18, 19 and 20, 21, respectively. In the last stage of the amplifier four vacuum tubes 22, 23, 24 and 25 are shown. As many tubes or as many stages of amplification as may be found necessary may b'e employed. The amplifier illustrated is of a type which is sometimes referred to as a direct current amplifier, since it is adapted to amplify impulses of long duration. Inasmuch as the vacuum tube amplifier shown is of a type which is well known, and since its operation will be readily understood by those skilled in the art, there seems to be no necessity for entering upon a detailed description of it. It may be well to point out, however, that each of the elements 26 to 31 inclusive is a high resistance clement and that the batteries 32, 33 and 34 are grid biasing batteries which are preferably arranged to render their respectively associated control electrodes or grids of negative potential with respect to filament.

Each half of the divided output circuit of the last amplifier stage includes an electromagnet coil 35, 36 and the winding ofy a relay 37, 38, respectively. Relay 37 is inserted in series with coil 35 and relay 38 is in series with coil 36. It may be found desirable to provide condensers 39 and 40 in shunt to the windings of the relays 37 and 38, respectively, in order to provide a low impedance ath for the impulses of short duration. ere these condensers are found to be unnecessary they may be omitted.

The electromagnct coils 35 and 36 are adapted to actuate an armature 41 which is (ill pivoted at 42 (see Figs. 4 and 6). Integral with armature 41 is an escapement lever 43 which alternately engages the teeth of the two escapement wheels 44, 45. These escapement wheels are rigidly mounted on a. shaft 46 with which they rotate and are angularly displaced with respect to each other by half the pitch of their teeth. Shaft 46 is rotatably driven by friction drive 47 but its rotation is under the control of the escapement mechanism comprising the two escapement wheels 44, 45, escapement lever 43, armature 41, and electromagnet coils 35 and 36.

When an impulse of a given polarity is transmitted over the cable conductors a current flows through resistances 26 and 27 in series and a difference of potential is developed thereby across the cxtreme terminals of these resistance elements. Accordingly, the potential of the control electrodes of the amplifier tubes 18 and 19 is changed. The potential of one of these control electrodes becomes more negative while that of the other becomes more positive when considered with respect to the potential of the filament. Ordinarily these control electrodes are maintained at such a negative potential that in the absence of any received impulses no current will flow in the output circuits of amplifier tubes 18 and 19. The same is, or may be, true of the succeeding amplifier stages. It is evident then that, during the reception of any impulse, plate current fiows in only one-half of the divided output circuit of the last amplifier stage. The polarity of the received impulse determines in which half of the divided output circuit current will fiow. In response to Isuccessive alternations of the received impulses, current flows alternately in the two halves of the divided output circuit of each amplifier sta e and accordingly current flows alternate y through coils 35 and 36 and through the windings of relays 37 and 38.

In response to the alternate energization of coils 35 and 36 the escapement lever 43 oscillates between escapement wheels 40 and 41 and permits the rotation of shaft 46. As long as the commutator 10 continues to rotate uniformly, that is, without interruption, the escapement lever 43 oscillates at a corresponding rate without interruption. As each segment of the commutator 10 comes into contact with the brush 13 one or the other of electromagnet coils 35, 36 is enel gized and the escapement lever 43 is moved out of engagement with one escapement. wheel and into engagement with the other. Each impulse, therefore, permits the rota tion of shaft 46 through an angle corresponding to one-half the pitch of the teeth of the escapement wheel. At each successive step of the escapement wheels the type,

wheel is rotated just enough to move a s ucceeding character into the' printing posltion.

A few of the type wheel characters are blanks.

When an impulse of a relatively long duration is transmitted one of the coils 35, 36 is energized for a correspondingly relau tively long period, with the result that the rotation of shaft 46 is interrupted for a period of time corresponding to the duration of the long impulse.

Type wheel 48 is connected to shaft 46 and is rotatable therewith while at the same time it is slidahle axially on that shaft. There are two parallel rows of type characters arranged peripherally on the type wheel (see Fig. 4). (lne of these rows includes capital letters together with numerals and other characters while the other row includes lower case letters together with numerals and other characters. When a key 8 at the transmitting station corresponding with any numeral, letter or other character or with a blank space on the type wheel is pressed the type wheel 48 is automatically stopped in the manner previously described with the corresponding numeral, letter or other character or blank space in the printing position.

Upon receipt of an impulse of long duration resulting from the operation of one of the transmitting keys one or the other of the slow acting relays 37, 38 (depending upon the polarity of the impulse) is operated and closes a contact in the local circuit of the printing magnet 4f) (see Figs. 2 and 3). The circuit connections shown in Fig. 3 have been omitted in Fig. 2 because they could not be clearly shown in that figure without tending to confuse. An armature lever 50 (see Fig. 7) adapted to be actuated in response to energization of printing magnet 49 is pivoted at 51 and connected through a link 52 to a lever arm 53 one end of which is pivoted at 54 and the other end of which carries a rubber printing roller 55. A paper tape 56 is arranged to pass between type wheel 48 and printing roller 55 and a twocolor typewriter ribbon 57 is disposed between the paper tape 56 and type wheel 48.

The paper tape passes between two rubber rollers 58 and 59 the former of which is mounted on a shaft 60 to` which is secured a ratchet wheel 61 adapted to be actuated by the pawl 62 which is carried by the armature 50. When the printing magnet 49 is energized and the armature 50 thereby actuated the pawl 62 engages a fresh tooth. Upon deenergization of the printing magnet 49 the armature 50 is restored to its normal position and the ratchet wheel 61 together with roller 58 is rotated once while at the same time the printing roller 55 is raised. The rotation of roller 58 moves the paper tape 56 longitudinally the proper distance for the spacing of the printed characters.

The two-color typewriter ribbon 57 passes through a ribbon guide 63 which is adapted to be moved transversely of the ribbon thereby moving the ribbonl into either of the two color' ositions similarly to the action of the rib on guidein an ordinary typewriter. The mechanism for operating the ribbon guide for the purpose of changing colors is clearly illustrated in Fig. 5 wherein is shown a wheel-cam 64 which is mounted on a shaft 65 to which is secured a driving ratchet wheel 66..4 The wheel-cam 64, shaft 65 and ratchet wheel 66 are adapted to be rotated step-by-step by the driving pawl 67 which is pivotally connected to the armature 68 of an electromagnet 69. Electromagnet 69 is labeled in Fig. 3 as the color shift magnet and will for convenience be referred to hereinafter by that term. The ratchet wheel 66 is rotated one step upon deenergization of the color shift magnet 69 as will be evident from an examination of Fig. 5. The ribbon guide 63 is pivotally connected to a cam-follower lever arm 70 which is pivoted at 71. A lug on the camfollower lever arm 70 bears against the periphery of cam 64 being held in engagement therewith by a spring 72. Each time the shaft 65 is rotated one step the cam 64 is rotated through an angle corresponding to one-half the pitch of its teeth. -In Fig. 5 the cam-follower lever arm 70 is shown in engagement with one of the hi h points of the cam wheel. Upon shaft 65 eing rotated one step from the position shown in Fig. 5 the cam-follower lever arm will move into a position wherein it engages the short radius of the periphery of the cam-wheel. It is evident that by this operation the ribbon guide together with the ribbon passing therethrough is moved laterally so that the alternate half of the ribbon is brought into active position and therefore the color of the printed impression changed.

The typewriter ribbon 57 is carried by two rotatable ribbonF spools 73 and 74 which are driven alternately by mitre gears 75, 76 and 77, 78. The shaft 79 which carries gears 76 and 77 is slidable longitudinally and onl y one of the gears 76, 77 is engageable wit its mate at any one time. A pair of bell cranks 80, 81 engage, individually, shifting sleeves 82, 83 which are carried b shaft 79. The bell cranks 80, 81 are pivote at 84, 85, respectively. A ratchet wheel 86 is arranged to drive shaft 79 and the latter is adapted to slide longitudinally therethrough. A driving pawl 87 drivingly engages the ratchet wheel 86 and is pivotally attached to armature 50 of the printing magnet. Upon each energiaztion of the printing magnet the ratchet wheel 86, shaft 79, and gears 76, 77 are rotated one ste One or the other of the ribbon spools 73, 4 is thereuponl rotatably driven one step. 'The spool driven depends upon which pair of mitre gears 75, 76 or 77, 78 happens to be engaged.

Near each end of the ribbon 57 there is attached thereto a metal clip 88 (only one being shown-see Fig. 7). These metal clips operate to engage the bell cranks 80, 8l, re-' spectively, and cause the shaft 79`to move longitudlnally thereby disengaging one pair of mitre gears and engaging the other pair. In Fig. 7 the mitre gears 77, 78 are engaged while gears 75, 76 are disengaged. The ribbon spool 74 rotates, under these conditions, in the direction indicated by the arrow thereon. The clip 88 is shown inFig. 7 in engagement with bell crank 8() and about to move the latter about its pivot 84 thereby effecting alongitudinal shift of shaft 79 and consequently a reversal of the direction of movement of ribbon 57,.

The mechanism for shifting the type wheel axially along the shaft 46 so as to bring one or the other of the two rows of type into operating position is illustrated most clearly in Fig. 4." This mechanism is similar to the color shifting mechanism and comprises a rotatable cam wheel 89 mounted on a shaft 90 to which is also secured a ratchet wheel 91. This cam is driven stepby-step by the ratchet wheel 91 and actuating pawl 92 which is attached to the armature 93 of the type shifting magnet 94. Armature 93 is pivoted at 95. A cam-follower lever arm 96 pivoted at 97 has a lug which bears against the periphery of cam wheel 89 and has a yoke 98 at its free end by which it engages a groove in the hub of the type wheel 48. 'It is plain that in response to rotation of the cam Wheel 89 the cam-follower lever arm oscillates and that the type wheel is moved axially along the shaft 46 from one position to the other and back. In each of the two extreme axial positions of the type wheel one row of type thereon is disposed opposite the printing roller 55. In Fig. 4 it will be seen that the row of type including the upper case letters is disposed opposite the printing roller. When the cam wheel 89 is rotated one step from the position shown in Fig. 4 the type wheel is Amoved into its other position wherein the row of type including the lower case letters is disposed opposite the printing roller.

Having described the mechanism by which the two-color ribbon is shifted and the mechanism by`which the type wheel is shifted from one position to the other and back, the circuit arrangement and connections whereby these mechanisms can be actuated at the proper time will now be considered.

In Figs. 2 and 4 there are shown two circuit making and breaking discs 99 and 100, respectively. These discs are mounted on and rotatable with shaft 46. Diagrammatic face views of these discs are shown in Fig. 3. The function of the discs is to make and break the local circuits of the printing magnet and shift magnets at the proper time. In Fig. 3 the discs are shown more or lessy diagrammatically. The portions shown cross hatched on the lface of each disc are electrical conducting portions whereas the remainder of the surface is of insulating material. A number of brushes are shown arranged to make contact with the various conducting portions of the discs at certain times during each revolution. In Fig. 3 disc 99 is labeled color shift control disc and disc 100 is labeled type shift control disc. The former controls the local circuit of the color shift magnet 69 and the latter controls the local circuit of the type shift magnet 94. Both discs are included in the local circuit of the printing magnet 49. Switches 101 and 102 are manually operable switches and may be thrown into either of the two positions indicated.

The circuits shown in Fig. 3 can best be explained in connection with an explanation of the operation of the system. Suppose that it is desired to print consecutive sentences of received messages in different colors. First we will trace the circuit of the printing magnet 49. This circuit includes battery 103, contacts 104 and 105 either of which may bc closed depending upon Iwhich of the slow acting relays 37, 38 is actuated. The circuit also includes brush 106 which engages the conducting portion 107 of disc 99. Conducting portion 107 is connected through conductor 108 to conducting portion 109 of disc 100. The latter conducting portion is engaged by brush 110 which is connected directly to the printing magnet winding. It is evident that the printing magnet is energized by battery 103 whenever one of the contacts 104 or 105 is closed, providing both brushes 106 and 110 are in engagement with their respectively associated conducting portions 107 and 109. Each of those conducting portions is broken at one point so that if either brush 106 or 110 is in engagement with the insulating portion of its respective disc the printing magnet circuit is open even though one of ,the slow acting relays 37 or 38 is actuated.

The breaks in the circuit of the printing magnet effected by the breaks in the conducting portions 107 and 109 are for the purpose of preventing operation of the printing magnet and therefore preventing the paper tape being moved forward when the type shift magnet or color shift magnet is operated. The break in conducting portion 107 engages brush 106 when the type wheel is stopped in response to actuation of the color shift key at the transmitting station. Like- Wise the break in conducting portion 109 engages brush 110 when the type wheel is stopped in response to actuation of the type shift key at the transmitting station. If provision were not thus made for preventing the operation of the printing magnet when the type shift magnet or color shift magnet is energized there would be undesirable blank spaces on the printed tape. But when receiving messages in which the color or style of type of each succeeding sentence is changed the discs 99 and 100 never stop in a position where either of the brushes 106 or 110 are out of contact with their respectively assocated conducting portions. The three conducting portions 111, 112 and 113 on disc 99 control the color shift magnet 69 when the operation is such that each successive sentence is of a different color. When so operating the switch 101 is moved into engagement with the contact 114 thereby connecting with brush 115. Under the same conditions switch 102 is left in the off position shown in Fig. 3. Conducting portions 111,' 112 and 113 correspond respectively with sentence terminating punctuation marks, namely, a period, a question mark and an exclamation mark. lVhencYcr one of those conducting portions makes contact with the brush 115 the corresponding punctuation mark on thc type wheel is in the printing position. For example, if it be assumed that conducting portion 111 corresponds to a period then if the transmitting operator presses the period key, shaft 46 will rotate until Contact portion 111 engages brush 115 and in that position the shaft, type wheel and disc will stop. Each of the conducting portions 111, 112 and 113 are connected together and are electrically connected to another conducting portion 116 which 1s engaged by a brush 117. Brush 117 is connected through contacts 104, 105 to the color shift magnet 69. Also, brush 115 is connected in circuit with the color shift magnet. This local circuit includes battery 103. The ribbon is not shifted until the color shift magnet is deenergized as is evident from Fig. 5. I

Now suppose that it is desired to print messages at the receiving station with each consecutive sentence in a different kind of type, that is, capital letters and lower case letters, alternately. In that event the switch 101 is moved into the position shown in Fig. 3 and switch 102 is moved into engagement with contact 120. Conducting portions 121, 122 and 123 on disc 100 correspond to conducting portins 111, 112 and 113. In other words, each corresponds with a sentence terminating punctuation mark. The conducting portions 121, 122 and 123 are connected together and through conductor 130 to conducting portion 129. Accordingly, if the type wheel is stopped in a position wherein one of the conducting portions 121, 122 or 123 is engaged by brush 124 a circuit is closed through the type shift magnet 94, battery 103, contact 104 or 105, brush 128, conducting portion 129, conductor 130, conducting portion 121, 122 or 123, brush 124, switch 102 and conductor 131 back to the type shift magnet. The type Wheel is, therefore, shifted following the printing of each sentence terminating punctuation mark.

There now remains to be considered, the operation of the system when the type and color changes are effected entirely under the control of the transmitting operator-that is to say, when consecutive sentences are not printed in dilferent colors or different kinds of type. When so operating, the transmitting operator presses a type shifting key or a'color shifting key whenever he wishes' to change the style of type or the color. To effect a change of type a key is pressed which causes the disc 100 (Fig. 3) to stop in a position wherein conducting portion 132 engages brush 133. Switch 102 engages contact 134-having been moved into that position by the receiving operator. A circuit is thereby established from battery 103 through contact 104 or 105 depend-- ing upon which slow acting relay 37, 38 happens to be energized, brush 128, conductmg portion 129, conductor 135, conducting portion 132, brush 133, contact 134, switch 102, conductor 131 through the winding of type shift magnet 94 and back to battery 103. But when the disc 100 is in that position the local circuit of the printing magnet 49 is open because brush 110 is out of contact with conducting portion 109. 'This con` dition-.is illustrated in Fig. 3. The type shift magnet is accordingly energized and subsequently deenergized when the relay 37 or 38 drops back to normal. The type wheel is therefore shifted without operating the printing magnet and consequently without advancing the paper tape. Otherwise a change of type would involve making a space between letters whether the space was wanted or not.

A similar arrangement provides for operation of the color shift magnet without operating the printing magnet.

Vhen the transmitting operator presses the color shift key the disc 99 is stopped in a position wherein the conductin portion 137 is in contact with brush 138. rush 106 is then out of contact with conducting portion 107. The circuit of the printing magnet 49 is therefore open at brush 106 While the circuit of the color shift magnet 69 is closed. The circuit of the color shift magnet includes vbattery 103, contact 104 or 105, depending upon which of the two slow actlng relays happens to be energized, brush 117, conducting portion 116, conductor 139, conducting portion 137, brush 138, contact 140 (the switch 101 having been closed on contact 140), conductor 141 and color shift magnet 69. This magnet is therefore energized and subsequently deenergized as soon as the slow acting relay drops back to normal. When this occurs the two-color ribbon is shifted in the manner previously described. The circuit of the printing magnet is held open during the operation of the color shift magnet as just described in order to prevent the paper tape being advanced at that time.

I claim:

'1. In a printing telegraph system, a transmitting station and a receiving station. means at said receiving station for printing received messages under the control of said transmitting station, said printing means including two sets of type and a shifting mechanism for bringing either of said sets of type into operation individually and to the exclusion of the other, said shifting mechanism being automatically operable in response to a signal corresponding to a sentence terminating punctuation mark.

2. In telegraphy, the method of 'clearly setting of the sentences of received messages which consists in inscribing alternate sentences with one style of type and inscribing the other sentences with a distinctly different style of type.

In testimony whereof I affix my signature.

F OWLER MCCORMICK. 

